On Sun, 24 Jun 2007, Horace Heffner wrote:
> How quickly memory fades: > > "When I used a soda straw and blew upon a thread with all my might, > the dot in the mist only moved a little... Not at all like smoke, > they are more like carbon-fiber spiderwebs under high linear > tension... And now I suspect that chains of charged droplets or ions, if they move fast enough while in an e-field, behave much like a contiguous rope. But the forces connecting them are e-fields, not thin fibers. > > On the other hand, when a sharp liquid cone starts emitting a charged > > fiber, that's called "electrospinning." Viscous liquids applied to > > charged metal electrodes apparently will send out "spider webs" > > spontaneously. > > It still seems to me only experiment can tell which. I still think > you should be able to tell the difference by the signals. Just using an audio amp and a tiny electrode gives no easily detected signals. But in theory, as a droplet or ion approaches an electrode, the voltage on the electrode smoothly rises. If many charged droplets approach in a stream, then the electrode voltage will rise high. But then as each droplet actually touches the electrode, it has a vanishingly small effect on electrode voltage. All of the voltage step occurred as the droplet approched, and not as the droplet touched. (I think we are misled by macro effects where a spark leaps whenever a charged sphere is brought near a grounded plate.) Therefore, we'd need a grounded plate with microscopic orfices, and an electrode positioned a microscopic distance behind this plate. That way when each droplet approached, it would have no effect on electrode voltage. But when a droplet passed through one of the holes in the grounded plate, it would suddenly create a large step in voltage at the electrode. We have to electrically shield the droplet as it approaches, then only remove the shielding as the droplet is about to touch the electrode. I've never tried this test. > > ----------------- > | | > V Emitter | > P > _ Plate | > | T1 > | | > | | > -o-R1---G---R2-o- > | | | > o o o > V1 G V2 > > Fig. 1 - Circuit diagram for drop/thread detection > > > Fig.1 is another sample circuit for doing so. P is a smooth DC power > supply floating above R2 and T1 (one technical difficulty with this > approach). The plate current goes through R1 to ground G. This gives > two current proportional voltages V1 and V2 close to ground and thus > easily amplified (a major advantage). If the current is carried by > charged droplets then the current signals will be wildly different in > timing. If the current is carried by conductive filament then the > signals should be comparatively flat. It may be possible, depending > on needle choice and humidity, and/or possibly CO2 concentration, to > generate either mode. If the needle emitter is in conductive > filament mode, then it should be possible to instantly send a HF > signal injected by transformer T1, and which is not received at the > same magnitude when there is no filament. Further, if the plate is > bifurcated, (and another current sense resistor R3 added) and the > emitter moved from above one plate to above the other, then a droplet > beam (or dry air dry needle signal) should transition current from R1 > to R3 more gradually and smoothly than a conductive filament (or set > of multiple simultaneous filaments, which would give a step function). > > Regards, > > Horace Heffner > > > > (((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billb at amasci com http://amasci.com EE/programmer/sci-exhibits amateur science, hobby projects, sci fair Seattle, WA 425-222-5066 unusual phenomena, tesla coils, weird sci
